How many 9's between 1-100?

Discussion in 'Off Topic' started by SandEagle, Jul 26, 2009.

  1. SandEagle

    SandEagle Lifer

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    gah, i had to redo this many times... try figuring it out without writing anything down.

     
  2. Chaotic42

    Chaotic42 Lifer

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    10 for each number which ends in 9
    9 more for each number which begins with 9

    I'm going with 19.
     
  3. lyssword

    lyssword Diamond Member

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    same question as how many 7's are between 1-100
    20
     
  4. SandEagle

    SandEagle Lifer

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    wrong :)
     
  5. Chaotic42

    Chaotic42 Lifer

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    Ah, never mind. I'm an idiot.
     
  6. Poulsonator

    Poulsonator Golden Member

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    You're missing a key part of the question. How many 9's are there inbetween 1-100?

    It's 20 as you forgot to count the nine that begins 99.
     
  7. dahunan

    dahunan Lifer

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    got me too

    20.. right?
     
  8. pontifex

    pontifex Lifer

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    0.

    I don't see any 9s between "1-100"
     
  9. GeekDrew

    GeekDrew Diamond Member

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    there are two 9's in 99, chaotic42.
     
  10. IronWing

    IronWing Lifer

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    Every last one of them.
     
  11. Chaotic42

    Chaotic42 Lifer

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    Yup. It's 20 as long as he's talking integers.
     
  12. Arkaign

    Arkaign Lifer

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    :laugh:
     
  13. SandEagle

    SandEagle Lifer

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    this work too if you're a smartass ;)
     
  14. txrandom

    txrandom Diamond Member

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    9, there is only one.
     
  15. DrPizza

    DrPizza Administrator Elite Member Goat Whisperer
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    Forget about 100 for a moment, and write the units as 01, 02, etc., and start with 00.
    So, 00 to 99
    100 numbers, each two digits each, for a total of 200 digits.
    Each digit occurs with the same frequency, so 1/10th of the 200 digits are 9's.

    20



    While my method may seem a little harder at first, here's a followup question: how many 7's are there between 1 and 1 billion?
    (suddenly, you see the wisdom in DrPizza)


    Also, SandEagle, this is the easiest method to do without writing anything down. I think that most people who did it in their head wouldn't have counted two 9's for the number 99. Of course, there are 10 numbers that end in 9, and 10 two-digit numbers that begin with 9. So, that's 20.
     
  16. TruePaige

    TruePaige Diamond Member

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    Every number from 9 up contains 9 units, so I'll say you could also argue for 92.

    100-91 = 9
    99-90 = 9

    etc.. ;)
     
  17. IHateMyJob2004

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    Minues the duplicate that is known as 99
     
  18. her209

    her209 No Lifer

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    Technically, there are an infinite number of 9s between 0-100 because each number can be represented as a fraction.
     
  19. IHateMyJob2004

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    Holy crap, I read over the responses. WE are all idiots. Please lock thread. PLEASE! IS this really a good use of brain power? I jsut sent hte weekend reading the CMT annual reports.
     
  20. SoulAssassin

    SoulAssassin Diamond Member

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    this

    It is the most accurate answer to the question worded as is.
     
  21. videogames101

    videogames101 Diamond Member

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  22. Chronoshock

    Chronoshock Diamond Member

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    Depends on the base. In binary there is no such thing as 9

    1
    10
    11
    100
     
  23. Nik

    Nik Lifer

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    In the English language, there would be an infinite number of 9's between all numbers on the number line between 1 and 100.

    In the English language, there would be no 9's on the number line among 1 and 100.

    If the question is how many 9's are used to make any whole number between 1-100, the answer is 20. If the answer is how many times the number 9 appears between 1-100, the answer is once.
     
  24. DrPizza

    DrPizza Administrator Elite Member Goat Whisperer
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    I think you'd lose the argument for 92. I think you mean a much larger number, because using your argument, the number 90 contains ten 9's.

    Off the top of my head, I believe that's 496 nines.

     
  25. DrPizza

    DrPizza Administrator Elite Member Goat Whisperer
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